Ink jet printing apparatus with line sweep and incremental printing facilities

ABSTRACT

An ink jet printing apparatus is described having facilities for printing information in character locations, (boxes) each character location comprising a plurality of vertical columns of drop locations, and a number of characters comprising a line of information. Structures and circuits are included for insuring correct location of information within the character boxes and also providing for one mode in which characters are printed continuously line-by-line and another mode in which characters are printed incrementally character-by-character. During incremental printing, as well as the first character in a line or group of characters, provision is made for re-bounding the printhead back into the box of the character just printed, that is, prior to the next character box to be printed to insure that when the printhead starts up again for the next character that all drop components for that character, including any located in the immediate vicinity of the character boundary, are properly placed during printing.

United States Patent [191 Fowler et al.

[11] 3,834,505 [451 Sept. 10,1974

L INK JET PRINTING APPARATUS WITH LINE SWEEP AND INCREMENTAL PRINTINGFACILITIES [75] Inventors: Raymond L. Fowler; James D. Hill;

Richard W. McCornack; N. Kenneth Perkins, all of Lexington; Michael L.Sendelweck, Georgetown; Donald L. West, Lexington; Thomas H. Williams,Lexington; Krikor Yosmali, Lexington, all of Ky. [73] Assignee:International Business Machines Corporation, Armonlc, NY.

[22] Filed: Dec. 11, 1972 [21] Appl. No.: 313,919

[52] US. Cl. 197/1 R, 197/19, 197/66,

[51] Int. Cl. G01d 15/18 [58] Field of Search 101/D1G. 13; 346/75, 140;

[ 6] References Cited UNITED STATES PATENTS 2,872,013 2/1959 Wittwer197/66 2,902,133 9/1959 Walton et a1. 197/66 2,909,935 /1959 Dodge197/66 X 2,954,860 10/1960 Woodhead 197/19 3,260,340 7/1966 Locular etal. 197/19 3,292,530 12/1966 Martin 197/65 X 3,297,124 1/1967 Sims197/19 3,346,091 10/1967 Cralle, Jr. et al. 197/65 X 3,453,379 7/1969Holmes, Jr 197/19 X 3,519,115 7/1970 Smith 197/86X 3,562,761 2/1971Stone et al 346/ 3,572,489 3/1971 Schaefer 197/60 FINE .7 POSITION@RAHNG 1 7 COARSE BLANK UNBLANK SIGNAL Primary Examiner-Robert E.Pulfrey Assistant Examiner-E. H. Eickholt Attorney, Agent, or Firm-D.Kendall Cooper [57] ABSTRACT An ink jet printing apparatus is describedhaving facilities for printing information in character locations,(boxes) each character location comprising a plurality of verticalcolumns of drop locations, and a number of characters comprising a lineof information. Structures and circuits are included for insuringcorrect location of information within the character boxes and alsoproviding for one mode in which characters are printed continuouslyline-by-line and another mode in which characters are printedincrementally characterby-character. During incremental printing, aswell as the first character in a line or group of characters, provisionis made for re-bounding the printhead back into the box of the characterjust printed, that is, prior to the next character box to be printed toinsure that when the printhead starts up again for the next characterthat all drop components for that character, including any located inthe immediate vicinity of the character boundary, are properly placedduring printmg.

10 Claims, 11 Drawing Figures RAMP 4, M. 92 GENERATOR I h [AMPLIFIER'CHARGE ELECTRODE DEGATE g1|1NRACTFERR)SET GRATING AL M T DATA SOURCECHARACTER AMPL'F'ER -7 TIME I E END OF CHARACTER e 84 85 n EN A NA CT EA'OENERATOR K 1 LEFT MARGINHSLN [m [PRINT ,MARGIN END OF LINE SIGNALRESET FROM PROCESSOR LATCH ,PATENTEOSEPI 01914 FINE CRATING CHARACTERPOSITION COARSE CRATINC CHARACTER TIME HEAD CARRIER MOVEMENT MECHANICALESCAPEMENT RACK suit: m s

a.aa4. s05

J 102: I 103: i

I I I.

LCHARACTER BOX A CHARACTER BOXB ;I CHARACTER BOX 0 i I IOOb I W 5 h-I-I00 I A00 I000 I oo STOP i 4008 i IOI LEFT MARCIN CHARACTER POSITIONPmmmsm 01914 I "saw 20$ 5 FIG. 3

* CHARACTER SET SIGNAL FROM DATA SOURCE BLANK/UNBLAN END OF CHARACTERSIGNAL FROM LATCH LEFT MARGIN CHARACTER GENERATOR SET LEFT MARGIN- ENDOF LINE SIGNAL FROM PROCESSOR RESET OR CARRIER RETURN FROM KEYBOARDCARRIER RETURN PATEN sEPTmNTT 3.834.505

' SHEET 5 FIG. 4a.

PowER 0N RESET PRTNTcNARAcTER H RAMP GENERATOR INK ET HEAD T22 T READYCHARACTER I sYNc. CLOCK GENERATOR 156 PROCESSOR BLANK/UNBLANK 2.NAcNET|cCARDUNIT NEXT END OF CHARACTER 5.MAGNET|C /157 5% A TAPE UNIT PRINT T41CHARACTERQG LINES CLOCK CLOCK 1590 W'Efic LINES i AT 159/ v PRINTER 127CONTROL sTART 0F scAN ,cTRcuN NExT CLOCK FlG.'-4b

15)0 so i61 CHARACTER LINES FEEDBACK WMECHANICAL MAGNETS, PRINTER READYT52 FUNCTIONS SPECIAL MECHANICS PM 154 LOGIC CIRCUITS coNPARE END OFCHARACTER INK JET PRINTING APPARATUS WITH LINE SWEEP AND INCREMENTALPRINTING FACILITIES RELATED PATENT APPLICATION U.S. patent applicationSer'. No. 313,886 filed Dec. 11, 1972, entitled Ink Jet PrintingApparatus with Overrun of Printhead to Insure Better Visibility andCounter Control of Printing Locations, having J. W. Woods, et al., asinventors, and assigned to the same assignee as the present application.

REFERENCES OF INTEREST The following U.S. patents are of generalinterest: Rossetto, et al., U.S. Pat. No. 25,354; Stabler, U.S. Pat. No.2,656,106, Woodhead, U.S. Pat. No. 2,954,860; Sims, U.S. Pat. No.3,297,124; Locklar, et al., U.S. Pat. No. 3,260,340; Jones, et al., U.S.Pat. No. 3,512,137; Hayes, et al., U.S. Pat. No. 3,494,550.

The following IBM publications are of interest:

Reed Switch Contact Block authors, R. L. Burdick, et al., IBM TechnicalDisclosure Bulletin, October 1966, page 512.

Toggle and Momentary Reed Console Switch Assembly, authors, L. F.Dorius, et al., IBM Technical Disclosure Bulletin, May 1967, pages 1702and 1703,

The following IBM Customer Engineering Manuals are of interest:

Selectric Printer Instruction Manual, January, 1966, Form NO. 241-5032.

Selectric Typewriter, Service Manual, November, 1970, Form No. 241-5615.

Selectric II Typewriter, Service Manual Supplement, Form No. 241-5615(Supplement).

Magnetic Card Selectric Typewriter, Self Teach Course Summary, July,1969, Form No. 241-5581.

Magnetic Card Selectric Typewriter, Self Teach Instruction Manual, Vol.[1, June, 1969, Form No. 241-5580.

Parts Catalog, Magnetic Card Selectric Type writer, August, 1969, FormNo. 241-5584.

Pictorial Reference/Adjustment Manual, Magnetic Card Selectric"Typewriter, July, 1969, Form No. 241-5593.

BACKGROUND OF THE INVENTION AND PRIOR ART The Rossetto patent describesphotocomposing apparatus making use of a grating for determination ofcharacter increments. The Stabler patent describes a shaft positionindicator for recognizing direction of rotation of a shaft and having anassociated counting means. The Woodhead patent describes a counter forkeeping track of printer position.

The Sims patent describes a power typing system incorporating an IBMSelectric" printer with an associated magnetic tape storage unit withrecording and reading facilities. Line readjustment capabilities arealso described. The Locklar, et al., patent describes an apparatussimilar to the Sims system with provision for selection of informationon a character, word, and line basis. The Jones, et al., patentdescribes an automatic typing system incorporating an IBM Selectric Typewriter together with an associated magnetic card storage unit havingrecording and reading facilities. The Hayes patent describes anelectrical keyboard unit.

The Burdick, et al., and Dorius, et al., publications describe ReedSwitch Assemblies.

The various IBM Customer Engineering Manuals describe the Selectric"printer, the Selectric Model 11 printer, and the Selectric printer andmagnetic card unit in the IBM MC/ST.

SUMMARY OF THE INVENTION The ink jet printing system described herein isdesigned to operate both in line and incremental modes. During lineprinting, the carrier, on which are mounted the ink jet hardware andoptical sensor, is moved from left to right at a reasonably constantspeed not exceeding 10 inches per second and has a high carrier returnspeed of 40-50 inches per second. In the incremental mode, a clockspring and escapement rack allows the carrier to stop at 0.100 inchintervals while it moves from the left to the right side of the machine.Tab, Backspace and platen Index capabilities are also included. Anelectrical switch allows the machine to be operated in either mode ofprinting.

Ink drops are formed at a high frequency such as kiloHertz and propelledfrom a nozzle at a high speed, and are directed toward a document to beprinted with suitable plalcement of drops to form character matrices,such matrix comprising a predetermined number of vertical columns ofdrops, such as 24 and each column comprising a plurality of drops, suchas 40.

A raster scan is used to print the characters. Deflection of ink dropsin the vertical direction is by electrostatic action, while deflectionin the horizontal direction is primarily by mechanical motion. In orderto reduce the requirements on the velocity control of the mechanicalmotion of the head which generates the stream, a line grating is usedhaving a line to define each vertical column of drops. Where printing iscontinuous and the stream motion is in a constant direction, thisgrating is sufficient. However, since the head must start and stop thefine grating is supplemented by a second grating which has one line foreach character position. If the head is stopped short of a characterline, then the line can be used to indicate to the electronics when tostart printing the related character (i.e. when to look at the linegrating). This allows the mechanism greater freedom in where the headstops.

The system described here is operable on an incrementalcharacter-by-character basis wherein characters are defined by characterboundaries, individual characters having components close to theboundaries and incorporates facilities automatically operable toposition the printhead prior to the starting boundary of a character tobe printed to insure proper placement of components.

OBJ ECTS The primary object of the present invention is to pro- I videink jet printing apparatus having both line printing A still furtherobject of the present invention is to provide an ink jet printing systemhaving facilities for accurate and complete placement of charactercomponents. 2

The foregoing and other objects, features, and advantages of theinvention will be apparent from the following more particulardescription of the preferred embodiment of the invention as illustratedin the accompanying drawings.

DRAWINGS In the drawings: FIG. 1 illustrates an ink jet' printing systemincorporating a printer and having an associated magnetic cardrecording/reproducing unit with both line printing andcharacter-by-character printing facilities.

FIG. 2a illustrates various pulse waveforms provided for in the systemof FIG. 1, together with carrier motions encountered during incrementalprinting. FIG. 2b is a supplementary waveform showing a left marginsignal.

FIG. 3 illustrates a coarse and fine grating and associated circuits forcontrolling printing of information and charging of drops.

FIG. 4a is a block diagram of the ink jet printing apparatus of FIG. 1showing a number of significant control lines and suitable data sources.FIG. 4b is a block diagram illustrating some of the printer mechanicalsignals involved.

DETAILED DESCRIPTION FIG. 1 illustrates an ink jet printing systemincorporating a typewriter l with an associated magnetic cardrecording/reproducing unit 2. Card unit 2 is shown for convenience onlysince by inspection of FIG. 4a, it is apparent that other kinds ofstorage units, recordinglreproducing units, and the like, may be used inthe system. Typewriter 1 has the usual keyboard 3 which preferably is ofthe electrical type referred to in some of the IBM Customer EngineeringManuals listed previously. It may also be of the type described in theHayes, et al., patent. Printer 1 incorporates an ink jet head assembly 4arranged for travelling movement from left to right (and conversely)adjacent a document 7 to be printed. Assembly 4 has an ink drop nozzleand an associated grating 8 with an upper incremental column locationscale and a lower character scale as shown in greater detail in FIG. 3.Printer '1 may be provided with various control buttons 10, ll, 12 andl3for automatic, line, word, and character printing, respectively. Otherkeybuttons 15-18 concern mode selection, that is, line printing orcharacter printing, playback, adjust, and skip, respectively.

Reference is made to the various Selectric" typewriter manuals referredto previously for description of other keyboard facilities and otherfeatures of the printer. The magnetic card unit 2 has a load slot 25 anda track indicator 26. Also provided on unit 2 is a card eject button 27,a track ste'pdown button 28 and a track stepup button 29 for relocatingthe scanning transducer with respect to the various tracks on the card.Reference is made to the various magnetic card manuals and the Jones, etal., patent for a description of facilities in the card unit. It isunderstood, of course, that other kinds of storage facilities, cardunits, tape units, processors, and the like can be substituted for unit2 including as an example, the magnetic tape unit set forth in the Simsand Locklar, et al., patents. Printer 1 incorporates a left margin reedswitch 30, a drop carrier return reed switch 31 and a right margin reedswitch 32. These may be of the type set forth in the Burdick, et al.,and Dorius, et al., publications.

FIG. 2a illustrates various mechanical movements encountered in thesystem of FIG. 1 during movement of head assembly adjacent document 7,while FIG. 3

represents circuitry for deriving the pulses from the fine and coarsegrating 8. FIG. 2b illustrates a left margin signal 61 with portion 61arepresenting closure of switch 30 indicative of the left margin zone,portion 61b indicating transfer of switch 30 and portion 610 indicatingprinting zone. Signal 61 is combined with character signal 62 fromportion 8b of grating 8 to control printing of the first character.Portion 62a reflects overrun of the grating in an incremental mode.

With mode keybutton 15 in line mode, head assembly 4 moves from the leftof margin switch 30 to the right across document 7 to print charactersin a continuous fashion. At the end of each line, a carrier returnoperation is performed as determined by the location of the switch 32,FIG. 1, or as a result of a line ending code from the data source, andhead assembly 4 returns beyond the left margin at switch location 30. 1

Mounted on head assembly 4 for translational movement adjacent grating 8is a sensor assembly such as that shown in FIG. 6. This comprises asupporting structure 30 incorporating a lamp 32 arranged to direct lightthru grating 8 to a reflecting lens 34. Light is then returned forreflection at by mirror 35 to a photosensor pickup 36 for development ofthe pulses such as those illustrated in FIG. 2a referred to a fmegrating pulses and coarse grating pulses, respectively. It will beunderstood that two photo-sensor assemblies such as that shown in FIG. 6would ordinarily be included in the nozzle assembly 4 in order to sensethe two sets of marks on grating 8.

Referring to FIG. 5, various structures incorporated in head assembly 4are illustrated. This includes apump 40 for directing ink from an inksupply conduit 41 on demand as a crystal 42 is energized, that is,pulsedat high frequencies. The rate of impuls'ing crystal 42 may be in therange of kiloHertz for example. Ink drops are emitted from nozzle 43 andpass through a charge electrode 44 forvariable charging in accordancewith the output of a charge amplifier to achieve deflection of the dropsin a column an amount representing the vertical height of the droplocation in any given character. As illustrated, the letter capital Sdesignated 50 comprises a number of vertical columns 51. The printing issuch that a sequence of drops forming vertical columns, each columncomprising a plurality of drops, such as 40 in number, is propelled fromnozzle 43 toward document 7 for the printing of the character involved.If drops are not required for printing, they are directed to a gutter 53for passage by means of a conduit 54 back to the ink supply,customarily. A pair of deflection plates 60 and 61 is positioned in thepath of travel of the drops leaving the charge electrode 44. A constanthigh potential is applied across plates 60 and 61 and this incooperation with the variable charge on the individual drops determinesthe amount of deflection as the drops are directed toward document 7.Grating 8a in this instance is shown as being positioned horizontallyrather than vertically as in FIG. 1, but the positioning is immaterial.

As indicated, the individual characters are located within characterboxes comprising perhaps 40 drop locations in height and 24 droplocations in width, that is, 24 columns wide.

If it is assumed that printer 1 is in a line mode and the system is in aplayback mode, appropriate positioning of a card, not shown, results incard unit 2.furnishing signals to the printer 1 to determine theprinting of characters. During a line printing mode, head assembly 1leaves the left margin which results in setting the left margin latch70, FIG. 3. An output indicating print is provided from latch 70 on line71 to And circuit 72 and remains at an up level until an end of linesignal is received from card unit 2 on line 75. As head assembly 4 movesadjacent grating 8, signals are provided to amplifier circuits 80 and 81from the respective portions 8a and 8b of grating 8. In order to handlevarious printing situations, portion 8a of grating 8 has marks thereonindicative of column locations in the individual characters. In the caseillustrated, the column lines are provided at 240 per inch in portion8a. During a line sweep mode, portion 8b of grating is not used.Amplifier 81 is degated by a signal on line 82 and character latch 85 isset by a signal on line 83. Latch 85 is reset at the end of a characterby a signal on line 84. Character position and width are determinedstrictly by character generator 130, FIG. 4a, to allow forproportionally spaced characters, if desired. An advantage is that thereis no requirement to maintain the velocity of head 4 constant.

In a typical situation, portion 8b of grating 8 has lines engravedthereon to indicate each character location encountered by head assembly4 as it traverses document 7 during printing.

The setting of latch 85 in conjunction with And circuit 72 providesgating for one input of And circuit 87 on line 86. The other inputoccurs from amplifier 80 when each fine mark is sensed in portion 8a ofgrating 8. Thereupon, ramp generator 90 is activated to provide a slopedsignal on line 91 to charge amplifier 92 which drives the chargeelectrode 44 previously discussed in connection with FIG. 5. Asindicated, the charge exerted on charge electrode 44 determines at whatdrop location a drop will ultimately arrive within a given column ofdrops in the character box on document 7. If no drop is required, thatis, it is to be directed to gutter 53, FIG. 5, then a blank signal online 93 to amplifier circuit 92 results in no charge on the drop and itlands in gutter 53. An unblank signal on line 93 enables amplifier 92 tocharge the particular drop occurring at that time from nozzle 43 with avoltage representative of the drop location to which it is directed ondocument 7.

INCREMENTAL MODE, CHARACTER-BY-CHARACTER PRINTING FIG. 2a illustratessome of the conditions occurring during incremental printing. that is,on a character-bycharacter basis. The movement of the carrier isindicated by line 100 in relation to a mechanical escapement rack 101 tobe described in greater detail later. The coarse grating indicatesindividual character boxes as shown in FIG. 2a. It is assumed that anincremental mode has been selected by depression of keybutton 15 onprinter 1, FIG. 1. Then appropriate signals are provided to enableprinting of the character and development of signals from the portions8a and 8b of grating 8. During incremental character printing by head 4adjacent document 7, detection of a character mark in portion 8binitiates an output from amplifier 81 to set latch 85 and the action ofthe circuit in FIG. 3 is essentially as previously described.

Mechanisms are provided that will be discussed shortly for relativelymoving the carrier backwardly in relation to the start of a characterbox to insure the proper placement of drops close to the character boxboundary. This is indicated, as an example, by portion 100a of line 100in FIG. 22a. Typically this increment amounts to 0.020 inch. When acharacter is to be printed then the carrier is released to move asindicated by portion 10% of line 100, further comprising a start upinterval 100b, FIG. 2a, and some slight overrun occurs as shown byportion 100C past the character box and into the next character box. Themechanisms are such that the carrier is returned into the character box7 just printed as shown by portion 100d of line 100. Thus,

the carrier is positioned prior to but in readiness for printing of thenext character in the subsequent character box. This is indicated byline portion e, further comprising start up interval 100e'.

It may be arranged that if printing of character box A in FIG. 2a is inprogress, receipt of the character signals for character box B duringthe interval 102 will enable the continued release of the escapementmechanisms and carrier 4 will then sweep on through character box Bperforming the printing of that character, as well. Thus, theover-shooting and backspacing to achieve start-up is not required inthat case. The same thing applies during the printing of character boxB. If the signal is received during the interval 103, then printing canproceed immediately into character box C without any stopping of thecarrier 4.

SYSTEM BLOCK DIAGRAM FIG. 4a is a system block diagram incorporating adata source 110, such as a processor, card unit, tape unit, or the likeand having various control lines -128 interconnected with a charactergenerator box and printer control circuits 131. Other lines 134-141interconnect the character generator 130 and printer control circuit 131with the head assembly 4.

In FIG. 4b the logic representing various mechanical functions hasinputs on lines ISL-156 providing control for various operationalcircuits 160 and ultimately to the printer mechanisms 161 with variousfeedback signals on lines 163.

CARRIER TRANSPORT MECHANISMS FIGS. 7-9 illustrate various mechanismsincorporated in printer] for facilitating movement of head assembly 4 oncarrier 5. Connected by a bracket 180 to carrier 5 is an escapement pawlassembly including an escapement pawl I81 mounted for engagement withthe escapement rack 101 previously referred to in connection with FIG.20.

Reference is made to the various Selectric typewriter manuals referredto previously, since many of the structures illustrated in FIGS. 7-8 aresomewhat comparable to the structures shown in those manuals. Attachedto carrier 5 is a cable 184 routed on pulleys 185-189 and coupled to arear cord drum 190 and a front cord drum 191. Two pulleys 189a and 18%are shown in place of the pulleys 188 and 189 in FIG. 9. The principlesof operation are the same.

As in the Selectric printers, a main spring 200 provides driving forceto move carrier 5 in the tab direction from left to right in FIGS. 7 and9. A motor 201, FIG. 9 provides driving force by a belt 202 and pulleys203 and 204 to a drive shaft 205 in order to move carrier 5 in thecarrier'return direction, that is from right to left, and also to windup main spring 200 in readiness for a subsequent movement of carrier 5from left to right. Several spring clutches 210 and 211 are provided inthe mechanism, more fully illustrated in FIG. 9. Positioned on theforward end of shaft 213 associated with main spring 200 is a face gear215 having an associated small gear 216 cooperating with a floatingcarrier return gear 217 arranged for coupling with spring clutch 210.Face gear 215 has an associated tab governor gear 220 that also floatson shaft 205. 1

For line printing, pawl 181 is released from escape- -ment rack 10]thereby enabling main spring 200 to drive carrier 5 by means of cable184 and cord drums 190 and 191. Face gear 215 and associated governorgear 220 together with frictionaly coupled clutch 211 and centrifugalgovernor 235 prevents the carrier from going faster than the operationalshaft 205.

At the end of each line, when carrier return is required, the carrierreturn shoe 225 is engaged against spring clutch 210 by mechanisms notshown thereby coupling the drive from shaft 205 through hub 227 which isfixed to shaft 205 through clutch 210 and by way of the carrier returngear 217 and gear 216 to reverse the rotation of shaft 213, associatedcord drums 190 and 191 and thereby to reverse the direction of cable 184in order to move carrier 5 from right to left in the printer.

During incremental, that is, character-by-character printing, pawl 181is released from rack 101 just long enough for movement of carrier 5 onecharacter location to the right. Prior to the completion of the movementof a complete character, pawl 181 moves back intoposition for engagementwith the next tooth on rack 101. This can be seen in FIG. 8. Associatedwith bracket 180 is a pin 182 riding in an elongated slot 181a in'pawl181. A spring 183 is connected between pin 182 and pin 196 that ismounted on the left most extremity of pawl 18.1. Slot 181a enablesengagement of pawl 181 but results in an over-shoot of carrier 5 pastthe character location as illustrated by portion 100c in FIG. 2a. Mainspring 200 tends to pull the entire carrier assembly to the right bymeans of cable 184. However, spring 183 is somewhat stronger than mainspring 200 and immediately after the over-shoot represented by portion1000 in 2a, spring 183 pulls bracket 180 and associated carrier 5rearwardly, that is to the left as indicated'by line 100d, FIG. 2a, intothe character box just printed and thereby, the carrier is located asufficient distance back of the next character to be printed. Thus, thecarrier 5 does not have to stop precisely at the boundary of theycharacter not to be printed, such as character box C, FIG. 2a.

While the invention has been particularly shown and described withreference to a preferred embodiment, it will be understood by thoseskilled in the art that various changes in form and detail may be madewithout departing from the spirit and scope of the invention.

What is claimed is:

1. In a printing apparatus having provision for successivelyincrementally printing individual characters in predefined characterlocations on a receiving member by a printhead, each of said characterscomprising components that are printed between and including a characterstarting position and a character termination position, a method forinsuring that all components of a character to be printed are properlyprinted within its respective character location, said apparatus beingoperable to print all components of each individual character during asingle character print cycle, each said print cycle comprising first,second and third cycle portions, comprising:

1. during thefirst cycle portion of each said print cycle relativelymoving said receiving member and said printhead from a position'prior tothe starting position of a character to be printed, said printheadhaving facilities for printing and being operable to print thecomponents of each individual character during the relative movement insaid first cycle portion;

2. during thesecond cycle portion of each individual character printcycle, overbounding said printhead past the termination position of saidindividual character into the next succeeding character location toinsure the printing of all components of said individual character priorto and including said termination position; and

3. during the third cycle portion of each individual character printcycle, invariably re-bounding and stopping said printhead back prior tothe starting position of the individual character to be printed in thenext character print cycle to be printed to thereby insure that astart-up interval exists prior to the starting position of the nextcharacter to be printed.

2. In a marking apparatus having provision for successivelyincrementally printing individual symbols in predefined symbol locationson a receiving member by a printhead, each of said symbols comprisingcolumns of markings that are printed between and including a symbolstarting'column position and a symbol termination column position, amethod for insuring that all components of a symbol to be printed areproperly printed within its respective symbol location, said appas ratusbeing operable to print all components of each individual symbol duringa single symbol print cycle, each said print cycle comprising first,second and third cycle portions, comprising;

1. during the first cycle portion of each said print cycle, relativelymoving said receiving surface and said symbol printhead from a positionprior to the starting position of a character to be printed, saidprinthead having facilities for printing and being operable to print thecolumnar components of each individual symbol during said relativemovement in said first cycle portion;

2. during the second cycle portion of each individual symbol printcycle, overbounding said printhead past the termination position of saidindividual symbol into the next succeeding symbol location to insure theprinting of all columnar of said individual symbol components in saidindividual symbol prior to and including said termination position; and

3. during the third cycle portion of each individual symbol print cycle,invariably re-bounding and stopping said printhead back prior to thestarting position of the individual symbol to be printed in the nextsymbol print cycle to thereby insure that a start-up interval existsprior to the starting columnar position of the next symbol to beprinted.

3. Marking apparatus for successively printing individual symbols inpredefined symbol locations, each of said symbols comprising columns ofmarking components that are printed between and including a symbolstarting columnar position and a symbol termination columnar position,an arrangement for insuring that all components of a symbol to beprinted are properly printed within its respective symbol location, saidapparatus being operable to print all components of each individualsymbol during a single symbol print cycle each said print cyclecomprising first, second and third cycle portions, comprising:

1. means for position a document for printing;

2. printhead means mounted for movement adjacent said document forselectively forming, propelling, charging and deflecting markingcomponents toward said document;

3. moving means operable during the first cycle portion of each saidprint cycle for relatively moving said document and said printhead meansfrom a position prior to the starting position of the symbol to beprinted in order to print a symbol on said document during said relativemovement;

. overbound means interconnected with said moving means and operableduring the second cycle portion of each individual symbol print cyclefor overbounding said printhead means past the termination position ofsaid individual symbol into the next succeeding symbol location toinsure the printing of all columnar marking components of saidindividual symbol prior to and including said termination position; andy 5. re-bound means interconnected with said moving means and operableduring the third cycle portion of each said print cycle, following theoverbounding of said printhead means for re-bounding and stopping saidprinthead means back prior to the starting position of the individualsymbol to be printed in the next symbol print cycle to thereby insurethat a start-up interval exists prior to the starting columnar positionof the next symbol to be printed.

4. lnk jet apparatus for successively printing individual characters inpredefined character'locations, each of said characters comprisingmarking components that are printed between and including a characterstarting position and a character termination position, an arto printall components of each individual character during a single symbol printcycle, each said print cycle comprising first, second and third cycleportions, comprising:

l. means for positioning a document for printing;

2. printhead means mounted adjacent said document for selectivelyforming, propelling, charging and deflecting marking components towardsaid document;

3. moving means operable during the first cycle portion of each saidprint cycle for relatively moving said document and said printhead meansfrom a position prior to the starting position of the character to beprinted in order to print a character on said document during saidrelative movement;

4. overbound means interconnected with said moving means and operableduring the second cycle portion of each individual character print cyclefor overbounding said printhead means past the termination position ofsaid individual character into the next succeeding character location toinsure the printing of all marking components of said individualcharacter prior to and including said termination position; and

5. re-bound means interconnected with said moving means and operableduring the third cycle portion of each said print cycle, following theoverbounding of said printhead means for re-bounding and stopping saidprinthead means back prior to the starting position of the individualcharacter to be printed in the next character print cycle to therebyinsure that a start-up interval exists prior to the starting position ofthe next character to be printed.

5. The apparatus of claim 4, further comprising:

6. means for relatively moving said document and said printhead means ona continuing basis in order 7 to print at least two characters insuccession;

7. degate means interconnected with said overbound means and saidrebound means, said degate means being operable to recognize occurrenceof at least two characters to degate said overbound and said reboundmeans to prevent operation of said overbound and said re-bound meansbetween said characters; and

8. gating means interconnected with said overbound means and saidrebound means, said gating means being operable to recognize the lastcharacter in a series to be printed to initiate operation of saidoverbound and re-bound means, whereby overbounding and re-bounding occuronly with respect to the last character printed in a series ofcharacters.

6. The apparatus of claim 4 wherein said marking components are arrangedin a plurality of columnar locations for each character printed, andfurther comprising:

6. grating means, said grating means comprising markings arranged infirst and second sets, the first set defining character locations andthe second set defining columnar locations in each character; and

7. means interconnected with said grating means for maintaining thelocation of characters and columns during printing operations, as wellas during said overbounding and re-bounding operations.

7. The apparatus of claim 6, wherein said grating 8. a coarse sensormeans and a fine sensor means, re-

spectively arranged for sensing said coarse and fine gratings, eachsensor means providing signal representative of the location ofcharacters and columns relative to the respective grating associatedwith each said sensor means during relative movement in said apparatus;and

9. means responsive to signals from said respective sensor means forcontrolling printing of characters and columnar components of saidcharacters.

8. The apparatus of claim 4, further comprising:

6. escapement means for controlling incremental movement of saidprinthead means relative to said document, said escapement meansincorporating a pawl element having an elongated slot, and saidescapement means further incorporating a pin element mounted forengagement with said slot in said pawl element, and said pawl elementfurther having a fixed pin element thereon; and

7. resilient means interconnected between said pin elements forestablishing said overbound and rebound actions when engagement of saidprinthead means with said escapement means occurs during printing. I

9. The apparatus of claim 4, further comprising:

6. first timing means providing signals for defining character locationsduring printing;

7. second timing means providing signals for defining marking componentlocations during printing; and

8. means responsive to signals from said first and second timing meansfor controlling printing of characters and marking components thereof.

10. The apparatus of claim 9, further comprising:

9. a data source, said data source providing signals to said firsttiming means for controlling the locations of characters.

1. In a printing apparatus having provision for successivelyincrementally printing individual characters in predefined characterlocations on a receiving member by a printhead, each of said characterscomprising components that are printed between and including a characterstarting position and a character termination position, a method forinsuring that all components of a character to be printed are properlyprinted within its respective character location, said apparatus beingoperable to print all components of each individual character during asingle character print cycle, each said print cycle comprising first,second and third cycle portions, comprising:
 1. during the first cycleportion of each said print cycle relatively moving said receiving memberand said pRinthead from a position prior to the starting position of acharacter to be printed, said printhead having facilities for printingand being operable to print the components of each individual characterduring the relative movement in said first cycle portion;
 2. during thesecond cycle portion of each individual character print cycle,overbounding said printhead past the termination position of saidindividual character into the next succeeding character location toinsure the printing of all components of said individual character priorto and including said termination position; and
 3. during the thirdcycle portion of each individual character print cycle, invariablyre-bounding and stopping said printhead back prior to the startingposition of the individual character to be printed in the next characterprint cycle to be printed to thereby insure that a start-up intervalexists prior to the starting position of the next character to beprinted.
 2. during the second cycle portion of each individual characterprint cycle, overbounding said printhead past the termination positionof said individual character into the next succeeding character locationto insure the printing of all components of said individual characterprior to and including said termination position; and
 2. printhead meansmounted for movement adjacent said document for selectively forming,propelling, charging and deflecting marking components toward saiddocument;
 2. In a marking apparatus having provision for successivelyincrementally printing individual symbols in predefined symbol locationson a receiving member by a printhead, each of said symbols comprisingcolumns of markings that are printed between and including a symbolstarting column position and a symbol termination column position, amethod for insuring that all components of a symbol to be printed areproperly printed within its respective symbol location, said apparatusbeing operable to print all components of each individual symbol duringa single symbol print cycle, each said print cycle comprising first,second and third cycle portions, comprising:
 2. during the second cycleportion of each individual symbol print cycle, overbounding saidprinthead past the termination position of said individual symbol intothe next succeeding symbol location to insure the printing of allcolumnar of said individual symbol components in said individual symbolprior to and including said termination position; and
 2. printhead meansmounted adjacent said document for selectively forming, propelling,charging and deflecting marking components toward said document; 3.moving means operable during the first cycle portion of each said printcycle for relatively moving said document and said printhead means froma position prior to the starting position of the character to be printedin order to print a character on said document during said relativemovement;
 3. during the third cycle portion of each individual symbolprint cycle, invariably re-bounding and stopping said printhead backprior to the starting position of the individual symbol to be printed inthe next symbol print cycle to thereby insure that a start-up intervalexists prior to the starting columnar position of the next symbol to beprinted.
 3. Marking apparatus for successively printing individualsymbols in predefined symbol locations, each of said symbols comprisingcolumns of marking components that are printed between and including asymbol starting columnar position and a symbol termination columnarposition, an arrangement for insuring that all components of a symbol tobe printed are properly printed within its respective symbol location,said apparatus being operable to print all components of each individualsymbol during a single symbol print cycle each said print cyclecomprising first, second and third cycle portions, comprising:
 3. movingmeans operable during the first cycle portion of each said print cyclefor relatively moving said document and said printhead means from aposition prior to the starting position of the symbol to be printed inorder to print a symbol on said document during said relative movement;3. during the third cycle portion of each individual character printcycle, invariably re-bounding and stopping said printhead back prior tothe starting position of the individual character to be printed in thenext character print cycle to be printed to thereby insure that astart-up interval exists prior to the starting position of the nextcharacter to be printed.
 4. overbound means interconnected with saidmoving means and operable during the second cyclE portion of eachindividual symbol print cycle for overbounding said printhead means pastthe termination position of said individual symbol into the nextsucceeding symbol location to insure the printing of all columnarmarking components of said individual symbol prior to and including saidtermination position; and
 4. Ink jet apparatus for successively printingindividual characters in predefined character locations, each of saidcharacters comprising marking components that are printed between andincluding a character starting position and a character terminationposition, an arrangement for insuring that all components of a characterto be printed are properly printed within its respective characterlocations, said apparatus being operable to print all components of eachindividual character during a single symbol print cycle, each said printcycle comprising first, second and third cycle portions, comprising: 4.overbound means interconnected with said moving means and operableduring the second cycle portion of each individual character print cyclefor overbounding said printhead means past the termination position ofsaid individual character into the next succeeding character location toinsure the printing of all marking components of said individualcharacter prior to and including said termination position; and 5.re-bound means interconnected with said moving means and operable duringthe third cycle portion of each said print cycle, following theoverbounding of said printhead means for re-bounding and stopping saidprinthead means back prior to the starting position of the individualsymbol to be printed in the next symbol print cycle to thereby insurethat a start-up interval exists prior to the starting columnar positionof the next symbol to be printed.
 5. The apparatus of claim 4, furthercomprising:
 5. re-bound means interconnected with said moving means andoperable during the third cycle portion of each said print cycle,following the overbounding of said printhead means for re-bounding andstopping said printhead means back prior to the starting position of theindividual character to be printed in the next character print cycle tothereby insure that a start-up interval exists prior to the startingposition of the next character to be printed.
 6. grating means, saidgrating means comprising markings arranged in first and second sets, thefirst set defining character locations and the second set Definingcolumnar locations in each character; and
 6. The apparatus of claim 4wherein said marking components are arranged in a plurality of columnarlocations for each character printed, and further comprising:
 6. meansfor relatively moving said document and said printhead means on acontinuing basis in order to print at least two characters insuccession;
 6. first timing means providing signals for definingcharacter locations during printing;
 6. escapement means for controllingincremental movement of said printhead means relative to said document,said escapement means incorporating a pawl element having an elongatedslot, and said escapement means further incorporating a pin elementmounted for engagement with said slot in said pawl element, and saidpawl element further having a fixed pin element thereon; and
 7. secondtiming means providing signals for defining marking component locationsduring printing; and
 7. resilient means interconnected between said pinelements for establishing said overbound and re-bound actions whenengagement of said printhead means with said escapement means occursduring printing.
 7. The apparatus of claim 6, wherein said grating meansdefines a coarse grating defining character locations and a fine gratingdefining columnar locations, and further comprising:
 7. meansinterconnected with said grating means for maintaining the location ofcharacters and columns during printing operations, as well as duringsaid overbounding and re-bounding operations.
 7. degate meansinterconnected with said overbound means and said rebound means, saiddegate means being operable to recognize occurrence of at least twocharacters to degate said overbound and said rebound means to preventoperation of said overbound and said re-bound means between saidcharacters; and
 8. a coarse sensor means and a fine sensor means,respectively arranged for sensing said coarse and fine gratings, eachsensor means providing signal representative of the location ofcharacters and columns relative to the respective grating associatedwith each said sensor means during relative movement in said apparatus;and
 8. gating means interconnected with said overbound means and saidrebound means, said gating means being operable to recognize the lastcharacter in a series to be printed to initiate operation of saidoverbound and re-bound means, whereby overbounding and re-bounding occuronly with respect to the last character printed in a series ofcharacters.
 8. The apparatus of claim 4, further comprising:
 8. meansresponsive to signals from said first and second timing means forcontrolling printing of characters and marking components thereof.
 9. adata source, said data source providing signals to said first timingmeans for controlling the locations of characters.
 9. The apparatus ofclaim 4, further comprising:
 9. means responsive to signals from saidrespective sensor means for controlling printing of characters andcolumnar components of said characters.
 10. The apparatus of claim 9,further comprising: